I got a mk 85 predator 50 cal in 1990 it was the first inline for me and it has the stainless barrel. With that fast twist it would shoot just about every sabot bullet i put down the barrel with extreme accuracy. I ordered some speer 200 gr .451 hollow points and some of the black sabots and used 90 grs. of 777 and found that when i shot deer they died from some extreme damage. The bullets would go in as a 45cal and come out as a hand grenade. If it ran off it didn't go far and would leave a blood trail a blind man could follow. When the hogs started coming around where i hunted i changed to a 100 grs of 777 and started using 300gr flat top xtp's. The recoil was so bad i dropped back to 90grs. I killed many deer and hogs with that load but i found that the .451 240 gr.HP xtp's done just as good and i could handle the 100grs of 777. When the kit to replace the #11 percussion came out i got it and changed to the 209 primers it was a good upgrade due to the wet weather.